Shares in the troubled bank dipped 2% in response, potentially due to a “lack of fresh ideas”, said Neil Wilson from Markets.com.
“RBS, Northern Rock and a stint in Bermuda and Latvia seem to fit with Metro quite well,” he added, referring to Frumkin’s resume.
Frumkin, who was initially hired as chief transformation officer last September, will release his first set of results next week.
The stock, trading at 4,018p two years ago, is now worth a mere 191p.
It is the also sixth-most shorted share in the UK suggesting many think there is more bad news to come.
The dog-friendly bank has been under fire since revealing a massive accounting blunder in January 2019, prompting an investigation by the authorities.
Customers ended up withdrawing £2bn in funds, meaning that pre-tax profits collapsed 83% to £3.4mln in the half-year to 30 June and swung to a £3.3mln loss in the third quarter.
To keep afloat, the company has been raising cash through a £375mln share placing in May, a £500mln sale of a mortgage portfolio in July and a £350mln bond issue with an eye-watering 9.5% coupon in October.
Founder and chairman Vernon Hill left in October after months of pressure by investors, while chief executive Craig Donaldson was gone by December.
Hill, who launched the company in 2010, was already under fire over payments made to InterArch, an architect and interior design firm owned by his wife.
Shares were trading at 191.6p on Wednesday afternoon.